Most iron oxide is mined as iron ore. Every year millions of tons go into blast furnaces to make iron.
Various iron oxides
- Iron(III) oxide, reddish, commonly known as rust, found in the earth as haematite
- Iron(II,III) oxide, magnetic, black, found in the earth as magnetite
- Iron(II) oxide, black, rare, flammable, not stable at room temperature
- Iron(II) hydroxide, dark green hydrated iron oxide